Microsoft and Ford have unveiled a system to enable voice-activated music and telephone calls for car drivers.
More than 80% of US households use mobile phones
The "Sync" platform, introduced at the Detroit auto show, will be available in 12 Ford vehicles this year.
Drivers will be able to say contacts' names in English, French or Spanish, or tell the car which song they want to hear from their MP3 player.
"The market potential is absolutely enormous," said Mark Fields, Ford's president for the Americas.
In-car electronics are an increasingly important area in the battle for share in the US auto market.
Bill Gates says Sync will "enhance the pleasure and safety of driving"
More than 80% of US households use mobile phones and 60 million digital music devices have been sold there in what Ford called a "flourishing market".
The agreement is part of a constant quest by Microsoft, the world's largest software maker, for fresh markets beyond the home and office computer ones which it dominates.
Ford, meanwhile, hopes that new technology will help it solve the problem of dwindling market share even in its home US market.
Other car companies are developing in-house technologies, such as General Motor's Onstar system.
The Sync system develops technology Microsoft already provides to carmaker Fiat under a similar deal outside the US.